Purpose: 

Conventional modalities of external-beam radiation therapy (EBRT) are associated with high incidences of severe vision-threatening ocular and orbital toxicities when used to treat orbital malignancies. We investigate toxicities associated with high-dose volumetric modulated arc therapy (VMAT), a commonly used contemporary treatment modality for these tumors.

Methods: 

Retrospective analysis of malignant orbital tumors managed with adjuvant high-dose VMAT preceded by globe-salvaging surgical therapy (GST) or exenteration. Dosimetric quantitation of target volumes and critical structures was performed. Incidence and severity of ocular, orbital, and adnexal toxicities were evaluated and assessed with regard to conventional EBRT toxicities for orbital malignancies described in the literature.

Results: 

Eighty-four subjects (mean age = 65.9 ± 9.7 years) were included (N = 48 and N = 36 in GST and exenteration subgroups, respectively). Mean dose was 64.8 ± 2.1 Gy to the planning target volume. Dosing to critical structures typically did not surpass known tissue tolerance limits. Median follow up was 18.3 months. Visual acuity in the GST subgroup was not significantly different after VMAT (0.25 ± 0.06) compared with baseline (0.23 ± 0.02; P = 0.302). Whereas severe toxicities reported by major systematic analyses in the literature with older EBRT modalities were relatively common—for example, retinopathy (16–40%), optic neuropathy (16%), and corneal perforation (13%)—toxicities with VMAT were typically mild and less common. The most common toxicities with VMAT were mild dry eye (81.3%; 39/48), cataract (21.1%; 8/38 phakic eyes), and periocular dermatitis (15.5%; 13/84). Vision-threatening toxicities, including severe corneal pathologies, retinopathy, or optic neuropathy, were rare. There were no contralateral ocular or adnexal toxicities.

Conclusions: 

High-dose VMAT for orbital malignancies demonstrated low incidence and severity of eye-related toxicity, in contradistinction to adverse events reported from conventional forms of radiotherapy.

中文翻译：

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高剂量容积调制电弧放射治疗治疗眼眶恶性肿瘤的眼部、眼眶和附件毒性

 目的：

当用于治疗眼眶恶性肿瘤时，传统的外照射放射治疗（EBRT）方式会导致严重威胁视力的眼部和眼眶毒性的高发生率。我们研究了与高剂量容积调节弧疗法（VMAT）相关的毒性，VMAT 是这些肿瘤的当代常用治疗方式。

 方法：

对恶性眼眶肿瘤的回顾性分析，其中采用辅助高剂量 VMAT，然后进行眼球抢救手术治疗 (GST) 或切除术。对目标体积和关键结构进行剂量定量。根据文献中描述的眼眶恶性肿瘤的常规 EBRT 毒性，对眼部、眼眶和附件毒性的发生率和严重程度进行了评估和评估。

 结果：

纳入 84 名受试者（平均年龄 = 65.9 ± 9.7 岁）（GST 亚组和切除亚组分别为 N = 48 和 N = 36）。计划目标体积的平均剂量为 64.8 ± 2.1 Gy。对关键结构的剂量通常不会超过已知的组织耐受极限。中位随访时间为 18.3 个月。 VMAT 后 GST 亚组的视力 (0.25 ± 0.06) 与基线 (0.23 ± 0.02; P = 0.302) 相比没有显着差异。尽管文献中主要系统分析报告的较旧 EBRT 模式的严重毒性相对常见，例如视网膜病变 (16-40%)、视神经病变 (16%) 和角膜穿孔 (13%)，但 VMAT 的毒性通常较常见。温和且较少见。 VMAT 最常见的毒性是轻度干眼（81.3%；39/48）、白内障（21.1%；8/38 有晶状体眼）和眼周皮炎（15.5%；13/84）。威胁视力的毒性，包括严重的角膜病变、视网膜病变或视神经病变，很少见。没有对侧眼部或附件毒性。

 结论：

与传统放疗形式报告的不良事件相比，高剂量 VMAT 治疗眼眶恶性肿瘤的眼相关毒性发生率低且严重程度低。